While trying to maintain a question of mine by adding some more media, I bumped into the issue of not being able to embed YouTube videos. I asked in the Teachers' Lounge and was pointed to make a meta question stating my case.
Here are what I see as the immediate benefits of enabling (and advertising) YouTube support:
We gain the ability to embed full- and micro- screencasts to demonstrate things
A lot of what goes on here is explaining a process. Click here, do this, do that and shazzam, it should work. I don't suggest we remove the writing but it would be nice for the more complicated things if users could also do a small screencast on the topic to show you what's happening.
This is particularly relevant to very new Ubuntu users who may not be familiar with the terminology used to describe certain UI elements.
There's also scope for a lot of new material and guides through videos that may be more appealing to an audience that we don't currently attract.
software-recommendation threads become a whole lot more awesome
Like the post I'm trying to maintain, if I can add a demo of the application I'm trying to promote, it can save the user a lot of time deciding if it's really for them.
As it is we tend to get an awful lot of screenshots that rarely convey as much information as is needed to decide.
I feel like there are more cases for Flash but really even if it only improves just one post, it's worth it in my eyes.
To address a couple of concerns:
Flash Player is insecure/slow/buggy/evil/etc
There's no argument against it not being the ideal video delivery platform, it's the best of what's available to most users in a way that can be embedded. As HTML5 support increases perhaps this will alleviate the stress on Flash haters.
Actually YouTube already supports partial HTML5 embedding through an iframe. I'm not sure what it does if you don't have Flash but they claim this method, in time, will solve all plugin support issues. If SO aren't doing this, they should.
Videos may detract from written content
We have plenty of screenshots that enrich both questions and answers and they work well because people don't just dump a screenshot but go on to explain it. I think it's important that videos, like screenshots are only used to illustrate and not be the sole instruction on a post.
I did say a valid case would be full-on screencasts so there's a contradiction in my "rules" already. I still think they're a valid type of post but of course it depends on the context. If somebody is asking how to run a terminal command, a video is nigh-on worthless. If they're asking for a quick tutorial in how to do something in GIMP, a screencast becomes very relevant.
In short: The question decides how relevant videos are.
Videos detract from the professional nature of the site
I don't agree. Good, relevant videos for the right questions just improve the amount of content we're delivering.
Of course bad videos (random kids faceplanting, cute kittens, rickrolling, etc) shouldn't be tolerated. At all. I'm two-strikes-serious about that. You'll get a warning for the first infringement and get a suspension for any future junk.
Video isn't great for people who physically can't see it, be that because of some biological impediment or because they're choosing to use a browser or device that won't display the video.
I personally don't see a difference in this respect between videos and screenshots.